44 results about "Active cancellation" patented technology

A intelligent backhaul radio is disclosed, which can operate by zero division duplexing for use in PTP or PMP topologies, providing for significant spectrum usage benefits among other benefits. Specific system architectures and structures to enable active cancellation of multiple transmit signals at multiple receivers within a MIMO radio are disclosed. Further disclosed aspects include the adaptive optimization of cancellation parameters or coefficients.

A radio frequency receiver subject to a large in-band interferor employs active cancellation with coarse and fine cancellation signals, each with a respective radio frequency combiner, in order to increase the effective dynamic range of the receiver for weak signals of interest. One or both can be digitally synthesized. This is particularly applicable for co-site interference, whereby the interfering transmit signal is directly accessible. A similar system and method may also be applied to external interferors such as those produced by deliberate or unintentional jamming signals, or by strong multipath signals. An adaptive algorithm may be used for dynamic delay and gain matching. In a preferred embodiment, a hybrid technology hybrid temperature system incorporates both superconducting and semiconducting components to achieve enhanced broadband performance.

An active cancellation unit is disclosed for improving the noise cancellation between a transmitter and a receiver which are connected to an antenna using a duplexer, the unit comprising a coupler sampling a signal to transmit provided by the transmitter, a cancellation duplexer having characteristics similar to the duplexer and receiving the sampled signal to provide a simulated signal and an active component receiving the simulated signal and providing an amplified signal having a phase 180 degree shifted with respect to the simulated signal; and a coupler for injecting the simulated signal at the receiver.

A wireless repeater comprises dual cancellation loops. The wireless repeater includes an active cancellation loop and a passive cancellation loops. The active cancellation loops reduces an environmentally induced signal component from a receive signal entering the repeater's amplifier. The passive cancellation loop reduces leaked signal component from the received signal.

A multi-fan apparatus and method incorporates mutual active cancellation of fan noise and / or vibrations. The multi-fan apparatus includes two or more fans circuits, each comprising a fan, a fan speed controller and a separate tachometer, and a fan phase controller. The phase controller is connected to at least one fan speed controller and to each tachometer. Each fan's speed is independently and dynamically maintained at the same set speed by the fan speed controllers using an independent control loops. A noise and / or vibration cancellation phase difference between fans is determined in order to achieve destructive interference of pressure waves and, thus, noise and / or vibration reduction, in pre-determined region of a system incorporating the multi-fan apparatus. The phase controller establishes and maintains this cancellation phase difference between the fans based upon feedback from the tachometers.

A method of imaging an object on one or more sensor pixels and with reduced glare. The method includes irradiating a scattering medium and the object behind the scattering medium, creating backscattered radiation and imaging radiation that are received on the one or more pixels. The method includes digitally adjusting a phase, an amplitude, or a phase and amplitude, of reference radiation transmitted onto the one or more sensor pixels, wherein the reference radiation destructively interferes with the backscattered radiation (glare) on the one or more sensor pixels while the object is imaged on the one or more sensor pixels using the imaging radiation.

A novel and useful 60 GHz frequency generator based on a third harmonic extraction technique which improves system level efficiency and performance. The frequency generator employs a third harmonic boosting technique to increase the third harmonic at the output of the oscillator. The oscillator generates both ˜20 GHz fundamental and a significant amount of the third harmonic at ˜60 GHz and avoids the need for a frequency divider operating at 60 GHz. The undesired fundamental harmonic at ˜20 GHz is rejected by the good fundamental HRR inherent in the oscillator buffer stage while the ˜60 GHz component is amplified to the output. The fundamental harmonic is further suppressed by an active cancellation by properly combining the two outputs. The oscillator fabricated in 40 nm CMOS exhibits a phase noise of −100 dBc / Hz at 1 MHz offset from a 60 GHz carrier and have a tuning range of 25%.

System and method to extend the data carrying capacity of a hybrid fiber cable (HFC) network by adding wideband RF signal capability above 1 GHz, and replacing the CATV amplifier devices with an improved type of Coax Domain Amplifier-Repeater (CDAR) device that, in addition to being a smart reconfigurable amplifier and cable signal diagnostic device, also segments the CATV cable portion of the HFC network into a series of smaller domains. The CDAR often alter RF signals from 5-865 MHz, while more freely passing RF signals over 1 GHz. Upstream capability is enhanced because the CDAR intercept 5-42 MHz upstream signals from each domain and convert to 1 GHz+ signals. Downstream capability is also enhanced because the CDAR can take efficiently encoded 1 GHz+ digital data, modulate it, and locally inject into each domain without crosstalk between domains. CDAR can use active cancellation, and active restoration techniques to improve performance.

A wireless transceiver includes a transmit path configured to generate a radio frequency (RF) transmit signal for transmission via an antenna, the transmit path generating a feedforward signal having at least one adjustable phase. A receive path is configured to receive an RF receive signal via the antenna. A circulator-based duplexer includes a circulator configured to couple the transmit signal from the transmit path to the antenna and to couple the receive signal from the antenna to the receive path. A controller is configured to process feedback from the receive path and to control the at least one adjustable phase to cancel portions of the transmit signal on the receive path.

A method of suppressing interference from remote transmitters operating to a first standard having frequencies overlapping those for a receiver operating to a second standard is provided. Such interference being increasingly common as a result of the deployment of multiple wireless transceivers within electronic devices either supporting multiple international standards, such as WiFi and WiMAX, or within typical wireless environments. Advantageously, the invention presents a means of actively cancelling interference from transmitters operating within the same frequency range as defined by the standard. The active cancellation accordingly allows improved performance for systems with very low received signal powers, such as GPS, in addition to wireless data communications standards. An exemplary embodiment providing active cancellation through delaying the portion of the received signal according to the first standard adjusting both the amplitude and phase by means of polar modulation prior to summing this signal with the received signal to provide a receive signal within which the first standard signal is nulled. Control of the polar modulator being determined in the exemplary embodiment by minimizing received power after passband limiting filters.

An apparatus and method for active cancellation of interference at a hearing assistive devices are presented. The apparatus includes an interference cancellation circuit for cancelling an interference component of a composite signal, and an activator circuit for enabling interference cancellation circuit. The interference cancellation circuit generates an estimated replica of the interference from an interference profile, inverts the replica to form a cancellation waveform, then adds the cancellation waveform to the composite signal to cancel the interference component. An interference profile can be provided by performing a training sequence on a composite signal to detect a repetitive signal and building a profile using its parameters, retrieving a profile stored in memory, or using an antenna to capture an RF signal. The activator circuit may enable the interference cancellation circuit when RF energy is detected, when composite signal characteristics match one or more stored profiles, or in response to user input.

A radio frequency receiver subject to a large in-band interferor employs active cancellation with coarse and at least one cancellation signals, each with a respective radio frequency combiner, in order to increase the effective dynamic range of the receiver for weak signals of interest. One or both can be digitally synthesized. This is particularly applicable for co-site interference, whereby the interfering transmit signal is directly accessible. A similar system and method may also be applied to external interferors such as those produced by deliberate or unintentional jamming signals, or by strong multipath signals. An adaptive algorithm may be used for dynamic delay and gain matching. In a preferred embodiment, a hybrid technology hybrid temperature system incorporates both superconducting and semiconducting components to achieve enhanced broadband performance.

An engine mount structure is provided with active vibration mechanisms which are attached in the vicinity of the engine mount to prevent engine vibrations from propagating into the engine mounting structure, for example, the wing or fuselage structure of an aircraft. Additionally, sensors are provided on the engine and / or wing / fuselage structure to provide control signals to the active vibration mechanisms so that the active vibration mechanism react to the sensed data to minimize the vibration transmissibility from the engine into the wing / fuselage.

Method for reducing air wave and / or magnetotelluric noise in controlled source electromagnetic surveying by either shielding the source (61) from the air interface, shielding the receivers from downward traveling electromagnetic energy, or by employing a second source (62) to preferentially cancel the air wave (and MT) part of the signal, or a combination of the preceding.

A radio system comprises a power source and a power amplifier circuit coupled to the power source on a power line. The radio system also comprises an active cancellation circuit. The active cancellation circuit comprises a bi-directional DC-DC converter. The active cancellation circuit is configured to cancel low-frequency emissions from the power amplifier circuit on the power line.

A logging tool having a tool body, which can be positioned in a fluid-filled borehole, including a receiver section and a dipole transmitter; wherein the dipole transmitter includes a transducer with a shell having a reaction mass and a motor located therein, the motor operatively connecting the shell and the reaction mass such that only an outer surface of the shell is in contact with the fluid in the borehole. This new type of dipole source for well logging involves shaking all or part (axially) of a dipole tool body to produce a pure, broadband acoustic dipole signal while at the same time coupling as little energy as possible into the tool body. Important variations on this idea include a linear phased array of shaker sources, and active cancellation of tool borne noise.

The invention discloses a power equalization method and a modulator for modulation of a specific harmonic elimination multilevel radio frequency pulse width. The method comprises the steps of: decomposing a specific harmonic elimination multi-level RF-PWM signal into a plurality of 3-level RF-PWM signals with equal pulse areas by using the area equivalence principle based on a multi-level radio frequency pulse signal output from the specific harmonic elimination multi-level RF-PWM, according to the rise and fall of the pulse outputting the multi-level RF-PWM signal; driving a rear-stage SMPA unit, so that multi-level RF-PWM output pulse sequence specific harmonics are eliminated, while achieving the power equalization between the rear-stage SMPA units and between the power tubes in the unit. The radio frequency pulse width modulator is based on the power equalization method, and generates a phase shift control signal for driving a rear-stage 5-level SMPA unit by using a digital delay line unit, thereby realizing active cancellation of a 3X times specific harmonic. The power equalization method for modulation of a specific harmonic elimination multilevel radio frequency pulse widthdoes not need an additional power equalization control circuit, which simplifies the modulator structure.

This disclosure provides methods and apparatus, including computer-readable media, for wireless power transfer and particularly active cancellation of undesirable electric or magnetic field emissions from a wireless power transmitter. In one aspect, the disclosure provides for an apparatus including a sensor, controller, and emitter, wherein the sensor is used to sense the electric or magnetic field emissions from a transmit antenna, the controller configured to determine the undesirable components of the field, and the emitter to generate a field to destructively interfere with the undesirable components.

The Energy spectral density of OFDM signals inherently rolls off slowly. Slow OFDM spectral rolloff has system level implications traditionally mitigated by some combination of the following: addition of bandlimiting filtering; use of significant guard bands of zeroed tones; and, guard time shaping. Each of these techniques negatively impact system performance and / or flexibility. This application presents a methodology for active cancellation of out of band spectral energy. The technique can be used by itself or in conjunction with above traditional methods to help control out of band emission. Examples of the use of the new technique are provided. Computational cost of the new technique is also discussed.

The present invention relates to a method for improving inter cell interference cancellation in an cellular radio communication system, said cellular radio communication system sending OFDM frames on an air interface, each OFDM frame comprising a pilot tones part and a payload part comprising a plurality of bursts. According to the present invention, the method comprising the step of: Sending on a sub channel a first set of pilot tones by the station sending a burst on said sub channel; Sending additionally in said frame and on said sub channel a second set of pilot tones by an additional station when a burst sent by said additional station starts on said sub channel. The present invention relates to a method for improving inter cell interference cancellation in an cellular radio communication system, said cellular radio communication system sending OFDM frames on an air interface, each OFDM frame comprising a pilot tones part and a payload part comprising a plurality of bursts.

Systems and methods are disclosed for active cancellation of transmitter leakage in a radio receiver that reduce power consumption and / or reduce noise in a desired receive frequency band. In some embodiments, in order to cancel transmitter leakage in a receive path, a cancellation signal is injected into the receive path in an upstream direction. By injecting the cancellation signal in the upstream direction, a noise component of the cancellation signal propagates through the receive path in the upstream direction and is either passed through a receive antenna or attenuated by an upstream component. Conversely, a desired component of the cancellation signal is reflected by an upstream filter and, thereafter, propagates through the receive path in the downstream direction to thereby cancel the transmitter leakage in the receive path. In this manner, active transmitter leakage cancellation can be performed while minimizing degradation of receiver sensitivity.

A novel and useful 60 GHz frequency generator based on a third harmonic extraction technique which improves system level efficiency and performance. The frequency generator employs a third harmonic boosting technique to increase the third harmonic at the output of the oscillator. The oscillator generates both ˜20 GHz fundamental and a significant amount of the third harmonic at ˜60 GHz and avoids the need for a frequency divider operating at 60 GHz. The undesired fundamental harmonic at ˜20 GHz is rejected by the good fundamental harmonic rejection ratio (HRR) inherent in the oscillator buffer stage while the ˜60 GHz component is amplified to the output. The fundamental harmonic is further suppressed by active cancellation by properly combining the two outputs. The oscillator fabricated in 40 nm CMOS exhibits a phase noise of −100 dBc / Hz at 1 MHz offset from a 60 GHz carrier and have a tuning range of 25%.

Reducing, suppressing or canceling series parasitic inductance and / or resistive effects that affect the frequency response of components, elements and / or circuits in an electronic circuit or system that exhibit capacitance is disclosed. Noise generated by series parasitic inductance and / or parasitic resistance of the components, the physical orientation of the components, and / or the layout of components, devices and / or conductive tracks (board traces) on printed circuit boards within an electronic circuit or system is reduced, suppressed or canceled. The reduction, suppression or cancellation is achieved by adding a voltage source in series with a part or component of the electronic circuit or system that exhibits capacitance, the current source being adapted to deliver a compensating voltage of roughly equal magnitude and roughly opposite phase to parasitic voltage associated with the part or component.

An active cancellation system may be utilized to cancel interference, such as from transmitter leakage or self-interference in a transceiver of an electron paramagnetic resonance (EPR) spectrometer. The active cancellation system may be inserted between the transmitter and receiver. The active cancellation system may receive the output of the transmitter, and generate a cancellation signal with the same amplitude, but phase shifted relative to the self-interference signal. The cancellation system may include an attenuator / amplitude tuner, buffer, VQ generator, and phase shifter.

The invention discloses a delay optimization method for linear frequency-modulated signal active cancellation. First, a mathematical model of a synthetic echo signal after cancellation is built according to the generation process of a cancellation signal; then, an expression of cancellation gain is derived according to the energy change of the echo signal before and after cancellation; and finally, the influence of system delay on amplitude error and phase error of wave absorbing is obtained through numerical calculation, and the system delay is optimized. The cancellation effect is improved, and the cancellation performance of a cancellation system is improved.

An active cancellation matrix for process parameter measurements provides feedback paths for each test location wherein each feedback path is used to sense the applied voltage and the sensed voltage is used to adjust the source voltage for any variations along the input path. The devices under test are arranged in a row and column array, and the feedback and voltage input paths are formed along respective rails which extend generally parallel to a row of devices under test. Selectors are used to selectively route the outputs of the test nodes to a measurement unit such as a current sensor. The input voltages can be varied to establish current-voltage (I-V) curves for the devices under various conditions. In the example where the devices under test are transistors, each source input includes three voltage inputs (rails) for a drain voltage, a source voltage, and a gate voltage.

An active cancellation system may be utilized to cancel interference, such as from transmitter leakage or self-interference in a transceiver of an electron paramagnetic resonance (EPR) spectrometer. The active cancellation system may be inserted between the transmitter and receiver. The active cancellation system may receive the output of the transmitter, and generate a cancellation signal with the same amplitude, but phase shifted relative to the self-interference signal. The cancellation system may include an attenuator / amplitude tuner, buffer, VQ generator, and phase shifter.